Motors (electric motors) and dynamos (generators) have widely been used as rotary devices that convert electric energy into rotational energy and vice versa. The motor converts electric energy into rotational energy (torque) by rotation of the rotor including a commutator. In the motor, resistance loss and slide contact (friction) between the brush and the commutator caused by rotation of the rotor raise the temperature of the brush and the commutator.
In bonding of a brush (first piece) to a supporting portion (second piece) that supports the brush or bonding of a commutator (first piece) to a coil (second piece) as disclosed in Patent Documents 1 to 3, high soldering with a high-temperature solder (high-melting point solder) or brazing are used since the bonded pieces has high melting points.
Patent Document 1: Japanese Patent Application Laid-Open No. S61-132286
Patent Document 2: Japanese Patent Application Laid-Open No. H3-114679
Patent Document 3: Japanese Patent Application Laid-Open No. 2008-271743